The invention relates generally to signal analysis and, more particularly, to obtaining descriptive parameters for broad spectrum signals.
It is often desirable in the electronic communications art to measure and describe the parameters of a broad spectrum signal. Such measurements and description are particularly useful in the field of electronic counter-measures (ECM). Signals having a relatively constant amplitude over a well defined bandwidth and being relatively free from noise are relatively easy to characterize using a three decibel (dB) bandwidth definition. However, it is often desirable to characterize broad spectrum signals occurring in the presence of high noise levels, and broad spectrum signals which exhibit considerable variation. Such signals are much more difficult to characterize using prior art automatic methods and apparatus, which are often confused by high signal peaks or noise peaks. Moreover, where a signal exhibits a "slant", characterizing the signal in terms of upper and lower frequency levels defined by a 3 dB limit can be misleading. Therefore, manual methods of describing such signals have previously been required. That is, the characteristics of the signal have required measurement by visual estimation. Such prior art methods did not provide noise spectrum bandwidth measurements having the reliability and repeatability which is required for applications such as ECM system production testing.
It is therefore an object of the present invention to provide a method and apparatus for characterizing broad spectrum signals existing in high noise environments and which exhibit varying characteristics.
It is a further object of the invention to provide such a method which is both reliable and repeatable.
It is yet a further object of the invention to provide methods and apparatus for characterizing broad spectrum signals existing in high noise environments and exhibiting widely varying characteristics which can rapidly and economically provide the required measurements in a production environment.